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Bronchus-associated lymphoid tissue and immune-mediated respiratory diseases
Published in Phillip D. Smith, Richard S. Blumberg, Thomas T. MacDonald, Principles of Mucosal Immunology, 2020
Dale T. Umetsu, Bart Lambrecht
In comparison with the well-established role for NALT as an inductive site of mucosal immune responses (see Chapter 22), the role of BALT as an inductive site in humans is more controversial. Similarly, whether BALT structures have an overlying specialized epithelium containing microfold (M) cells, as do Peyer's patches, is controversial. The bronchial mucosa of infants and children contains large numbers of isolated lymphoid follicles in close contact with the surface epithelium (Figure 23.2). These lymphoid aggregates contain many small B cells surrounded by naive T cells, regulatory T (Treg) cells, and high endothelial venules, as well as many DCs. Under steady-state conditions, only a minority of the aggregates show germinal centers. Thus, BALT may be an important inductive site for immune responses, especially during childhood or in patients with lung disease.
Cells and Organs of the Immune System
Published in Constantin A. Bona, Francisco A. Bonilla, Textbook of Immunology, 2019
Constantin A. Bona, Francisco A. Bonilla
Bronchus-associated lymphoid tissue (BALT). Lymphoid tissue is associated with both the upper (nasal mucosa) and lower (lungs) respiratory tracts. The lungs contain several populations of lymphocytes: the intravascular pool, ten times larger than that found in the liver or kidney; the interstitial lymphocytes; and those in the bronchoalveolar space. There appears to be a slow exchange between the bronchoalveolar and recirculating cells. BALT has been well-described in certain experimental animals (e. g., rabbits), but is inconsistently found in humans. In fact, it appears more often to be a marker of certain disease states such as sudden infant death syndrome, Sjogren syndrome, and rheumatoid arthritis.
Pulmonary Immunology
Published in Lourdes R. Laraya-Cuasay, Walter T. Hughes, Interstitial Lung Diseases in Children, 2019
Hemant H. Kesarwala, Thomas J. Fischer
Bienenstock et al. defines BALT as that portion of the organized lymphoid tissue in the bronchial walls that is covered by a specialized lymphoepithelium,16 a single layer of flattened nonciliated epithelial cells present on the air (lumen) side of the bronchus. The typical capsule present in lymph nodes is absent. Animal studies show that BALT follicles are found most extensively at the bifurcation of the airways. Blood supply to these lymphoid aggregates is received from the pulmonary artery coupled with an extensive capillary network. This arrangement allows for antigens from other tissues to arrive at these sites, although primary antigen sampling is from the respiratory tract.
Decision-making in diagnosis of bronchus-associated lymphoid tissue lymphoma
Published in Baylor University Medical Center Proceedings, 2021
Tasnim Lat, Juan F. Sanchez, Meghan K. McGraw, Parsa Hodjat, Heath D. White, Carl D. Boethel
BALT, which is not tissue native to the lung, has been found more commonly in smokers than nonsmokers.5 BALT is thought to form secondary to chronic antigen stimulation in the setting of smoking or chronic inflammation due to autoimmune disease; the development of BALT lymphoma involves chronic inflammation perpetuating antigen-dependent B cells, eventually leading to the proliferation of monoclonal B cells.6,7 We found a high incidence of smoking (58%) in our studied population. BALT lymphoma also has a strong association with autoimmune disorders, particularly Sjögren’s syndrome, which increases the risk of developing lymphoma sixfold. Unlike mucosa-associated lymphoid tissue lymphoma of the stomach, which has a strong infectious association with Helicobacter pylori, BALT lymphoma lacks a strong known infectious etiology.8
Induction of mucosal immunity by pulmonary administration of a cell-targeting nanoparticle
Published in Drug Delivery, 2021
Tomoaki Kurosaki, Yuki Katafuchi, Junya Hashizume, Hitomi Harasawa, Hiroo Nakagawa, Mikiro Nakashima, Tadahiro Nakamura, Chikamasa Yamashita, Hitoshi Sasaki, Yukinobu Kodama
The lung controls breathing and is exposed to many pathogens, such as viruses and bacteria that cause respiratory infections. Those pathogens infect through the pulmonary mucosal membrane, so mucosal immunity must be induced to protect against respiratory infections. To prevent respiratory infections, mucosal immunity has an important role; however, intradermal and intramuscular administration of the vaccine cannot strongly stimulate mucosal immunity (Ito et al., 2003; Amorij et al., 2007). The mucosal immune system that induces secretory IgA is developed on the mucosal surface. Several APCs, such as dendritic cells and macrophages, have been reported to be located in the mucosal surface (Kopf et al., 2015). Furthermore, bronchus-associated lymphoid tissue (BALT) is found in the bronchiolar mucosa and is a lymphoid follicle that has a central role in respiratory tract mucosal immunity (Bienenstock, 1980). Pulmonary administration of the vaccine is expected to stimulate the mucosal immune system effectively. Therefore, we constructed the OVA/BK/γ-PGA complex to assess its usefulness as a vaccine administered via the pulmonary route.
A review of the fate of inhaled α-quartz in the lungs of rats
Published in Inhalation Toxicology, 2019
The location of granulomas in the pleura and LALN suggests that dust cells in the interstitium may distribute pleura through the pulmonary lymphatic channels because the pleural lymphatics run throughout the surface of the lungs toward the lung hilum (Lauweryns & Baert, 1977). In addition, the location of granulomas in BALT suggests dust cells move toward the exit of the translocation pathway, because BALT is considered a candidate exit site for dust cells to leave the luminal side of the interstitium (Bowden, 1984; Brundelet, 1965; Ferin & Oberdörster, 1992; Lauweryns & Baert, 1977). Incidentally, BALT is one of the mucosa-associated lymphoid tissues considered to be an inductive site for mucosal immunity. BALT presents on surfaces of mucosal tissues and is comprised of a variable numbers of follicles, interfollicular areas equipped with high endothelial venules, and efferent lymphatics (Pabst & Gehrke, 1990; Kuper, 2006).